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3/12/09

Growth Models Debunked, By God!

The Education Sector's "Are We There Yet?" offers a number of caveats in its analysis of Tennessee's growth model, as well as a refresher course on Zeno. But unless you are irrevocably committed to NCLB-type accountability, I'd skip the discussion of educational issues and enjoy the review of ancient Greek philosophy.

Tennessee's growth model measures student progress against benchmarks based on predicted or "expected" scores needed to attain proficiency in three years. This is an analytical construct, however. It can offer no insight into what should be expected of a teacher in a high poverty neighborhood school.

In a real world setting, what growth can be expected during a year when a student buried his grandparents, was incarcerated, was a victim of domestic abuse, was shot or stabbed, saw his mental illness spin out of control, or just gave into the peer pressure of the gang? How should expectations for teachers be adjusted for a class which brings so many social pathologies into a classroom that the "tipping point" is crossed, in comparison to teachers in charters or lower poverty schools? How should a teacher be held accountable under such a model for a principal who is not allowed or refuses to enforce the disciplinary code of conduct. Can the model be adjusted for the effect of a critical mass of special education students, i.e. are expectations adjusted when the percentages of students on IEPS passes 20% or 30% or 50%? (and does it matter if your students on IEPs are sweet kids with a reading disabilities or Seriously Emotionally Disturbed and on parole for violent offenses?)

Of course, none of my objections would be major if the model was used for purposes of diagnosis, science, or a "consumers’ report." We should pursue social science fearlessly, but we must not play dice with the lives of teachers by evaluating them with some theoretical work in progress.

At the risk of sounding too argumentative, I would especially like adjustments in the expectations for incoming students who can decode but not comprehend and whose education has been stunted by test prep, narrowed curriculum, and the other sins of NCLB.

My favorite passage of the report was "The Tennessee growth model will also reduce the number of schools identified by NCLB as falling short academically. This could be a positive change if it allows the state to focus more intensely on the lowest-performing schools." No! Models do not reduce or increase the number of failing schools. People do that.

If we want to focus more intensely on the lowest performing schools, which we should, then we should focus more intensely on the lowest performing schools. If we conclude, as we should, that both the status models and the safe harbor models of NCLB are incompetent, we do not need to embrace another statistical construct just because it is less primitive. We should use our judgments, buttressed by data, and not devise an elaborate set of algorithms that have no relation to the facts of school life. - John Thompson